ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
655 
axis of the nucellus, but not so sharply differentiated from the adjoining 
tissue as in Casuarina. The cells of this tissue divide into daughter- 
cells, of which some remain sterile and subsequently disappear, while 
others are the rudiments of embryo-sacs. 
The antipodals are to be distinguished at an early period in the 
embryo-sac of the hazel, clothed with cellulose-membranes, before 
the appearance of the egg-apparatus. They always contain three nuclei, 
the free nuclei of the embryo-sac being five in number. At the time 
of impregnation the antipodals have moved from their original basal 
position, and occupy a lateral situation much nearer to the micropylar 
than to the chalazal end of the sac. The sterile embryo-sacs recall the 
sterile megaspores of Casuarina. The apex of the pollen-tube reaches 
the summit of the embryo-sac at the point of attachment of the egg- 
apparatus. After impregnation the oosphere coats itself with cellulose ; 
and the formation of the embryo takes place in the ordinary way. 
(2) Nutrition and Growth (including- Germination, and Movements 
of Fluids). 
Latent Life of Seeds.* — From a series of experiments made on 
a variety of seeds, M. 0. de Candolle comes to the conclusion that in 
their latent life seeds pass through a period of suspended animation 
{ vie ralentie), in which all the functions of the protoplasm are quiescent, 
but from which they revive when again placed in conditions suitable 
for germination. This period of suspended animation may extend over 
an indefinite time, probably through a long series of years, aud the seeds 
may, during this period, be subjected to very low temperatures without 
losing their vitality. In the case of wheat, oat, and fennel the tem- 
perature was reduced as low as — 30° C. — and the experiment was re- 
peated as many as 118 times in succession on the same seeds — without 
injurious effects ; the greater number of the seeds of the sensitive jffant, 
however, succumbed to this temperature, and nearly all those of Lobelia 
JSrinus. This immunity appears to depend on the protoplasm of the seed 
passing into a completely inert state, incapable of either respiring or 
assimilating, before it is placed in the unfavourable conditions. 
Dispersion of Seeds, j — Sig. G. Lo Forte discusses the various con- 
trivances for the dispersion of seeds found in Angiosperms, and lays 
great stress on the part played by water in effecting the dissemination. 
These various contrivances are especially conspicuous in cases where 
there are a large number of species in a genus, or a large number of 
genera in an order ; and those are described in some detail which are 
found in the orders Cruciferae, Leguminosas, Umbelliferae, Compositae, 
and Labiatae. In the case of indehiscent fruits a very important function 
is performed by the mucilage which ultimately causes the decay or the 
rupture of the pericarp. 
Germination of Bromeliacese.j; — HerrF. Muller describes the struc- 
ture and mode of germination of the seed of some Bromeliaceae belonging 
to the tribe Tillandsieae. They are in many cases provided with a 
* Arch. Sci. Phys. et Nat., xxxiii. (1895) pp. 497-512. Cf. this Journal, ante, 
p. 497. t Nuov. Giorn. Bot. Ital., ii. (1895) pp. 227-57. 
J Ber. Deutsch. Bot. Gesell., xiii. (1895) pp. 175-82 (1 pi.). 
